On numerous occasions it is necessary to ensure that an item is securely identified, securely meaning that the identification means cannot be removed from the item and used for another item without evidence of tampering.
For application in retail of expensive goods, such as jewelleries, watches, and precious stones, a secure and unique identification is more and more requested to avoid fraud in the selling shop and in the supply chain from manufacturers to the end customer (buyers).
In many occasions it is needed to guaranty that the content of an object, e.g. a container, has not been fraudulently modified during a storage period or at any point along the supply chain since the sealing was affixed to the container.
The term “container” used in the present text has a broad meaning. It may be a building of which the door or the windows has been sealed, a box which content must not be altered or an electrical/water counter that must be opened only by authorised persons.
The term “sealing” is also used in a very general manner in the present text. It is not limited to the sealing of an object like a box but encompasses also the sealing of the security object itself. An example of this second definition is an operation of marking an object, like for example a suitcase during a trip, the marking having to remain attached to the object without a possibility of being taken off it, exchanged or altered before the end of the trip, or before the accomplishment of a checking operation, respectively.
There are many different types of sealing devices existing in today's market. These sealing devices are used in many applications such as, security seal for postal bags, security boxes, doors, and containers etc. The existing sealing devices are usually identified with various methods, like barcode, engraved serial number or even RFID tags. Those means of identification provide no direct evidence in the event of tampering with the sealing device other than by a visual check.
International patent application WO 93/12513 discloses a security-sealing device made of a support on which is fixed an electronic circuit comprising an antenna connected to a chip. Any attempt to peel or tear off the support would break the electronic circuit and prevents it from sending out its code when read by an external detecting device such as an RFID reader.
The above cited prior art security sealing device is efficient. There is, however, some disadvantages related to this type of device. For instance, if by any means the support is detached, e.g. unglued, from the electronic circuit without damaging the wire loop inside, the tag would still be functional, and therefore would not provide any electronic tamper evidence.
There is therefore a need to improve the tamper evidence of such security sealing devices.